I have just set up a new tank. The display is 185 and the sump is a 75 but will probably contain 50 gallons of water. I was wondering if it would be OK to use straight tap water for the initial water to begin the cycling process and then begin using RO/DI water as I make water changes and top off? My tap is 105 TDS and comes from a small private water system. Would there be any issue with residual minerals or chemicals after several weeks of water changes?